Some cards on some stuff Flashcards
What are haptonema?
- microtubule tentacle that aids in sensing/food collection in haptophytes
What are the 3 kinds of alveolata? What do all three have in common?
- apicomplexa: parasite
- dinoflagellates: a type of algae
- ciliophora: a free living protozoa
they all have cortical alveoli: flattened vesicles under the cell membrane
What are dinoflagellates?
- a type alveolate and a type of algae (with chlorophyll c)
- mostly flagellated
- most are phagotrophic
- ecologically important
- cause most toxic algae (fun fact)
- ~1/2 have plastids (photosynthetic)
- armoured dinoflagellates: have cellulose thecal plates in the alveoli
How do armoured dinoflagellates protect themselves?
- they have cellulose thecal plates within the alveoli
What are apicomplexa?
- parasites: a type of alevolate
- a major group of animal parasites (eg; malaria)
- invade host cells (intracellular)
- complex life cycle: sexual, two hosts
Describe the apicomplexan life cycle
- haploid dominant: may involve more than one host species
- 3 main cell types: merozites, gametes, sporozoites
- reproduce by m
Describe ciliophora
- a type of alveolate
- free living protozoa
cilia:
- often simple somatic (body) cilia
- complex structure also common
- nuclear dualism
What is nuclear dualism?
micronuclei and micronuclei
micronuclei: diploid, inactive; germ line, can undergo mitosis and meiosis
macronuclei (Mac): hundreds to thousands of micronuclei, transcriptionally active, reproduces through binary fission (asexual), degenerates during conjugation
What occurs during conjugation? where does conjugation occur?
- conjugation occurs in the nuclear dualism of ciliophora
- macronuclei degrade and micronuclei undergoes meiosis : haploid nuclei exchange and then fuse
do chloropohyta have sexual or asexual processes?
- both! Asexual is when it divides by binary fission and in the sexual process conjugation occurs and haploid nuclei are exchanged!
Describe the ciliate diversity
- some cells have an even covering of somatic cilia
- some have few cilia but a large oral apparatus (ocean plankton)
What are eukaryotic flagella also known as?
- cilia
- completely different from bacterial flagella
Describe the plastids of protozoa
- in many eukaryotes
- has 2 , 3, or 4 membranes
- descended from cyanobacteria: same properties: thylakoid membranes, 2 PS (oxygenic), and chl a
Describe chloroplastida
- a type of archaeplastida: land plants and ‘green alga’
- diverse
- most have a cell wall or scales of carbohydrates
shapes: flagellated, unicellular, macroalgae
What are the two kinds of chloroplastids discussed?
- prasinophytes : small flagellates, important in marine plankton, many have carbohydrate scales made intracelllulrly and chlorophycae: mostly freshwater, have thick cell wall to resist osmotic pressure, many colonial forms
What are haptophytes?
- a type of algae with chlorophyll c
- mostly flagellated, many with aflagellate stages
- ecologically important : mostly marine
- many are mixotrophs
- many have haptonema: microtubule tentacle
- most have mineralized coccoliths or carbohydrate scales
How are coccolith scales fused with the outer membrane?
- formed in the endomembrane and then the end-membrane fuses with the cell membrane and scale becomes a part of the existing scales
What are the unique hairs on stramenopiles called?
- mastigonemes: hairs on either side of flagella reverses the effect of flagellar beat: swims the other way!
Describe diatoms
- unicellular and colonial
- non flagellated (apart from gametes)
- characteristic silica frustule
- centrics (planktonic) and penates (benthic)
Describe the plastids in protozoa
- plastids are in many eukaryotes
- bound by 2,3, or 4 membranes
- descended from cyanobacteria: have thylakoid membranes, chlorophyll a, and oxygenic: 2 PS
Describe primary and secondary endosymbiosis in protozoa
- primary endosymbiosis: like mitochondria, cyanobacteria engulfed and not digested ; becomes primary alga
- secondary endosymbiosis: plastids only: primary algae absorbed to become secondary alga; complex with 2,3, or 4 membranes
What are archaeplastida?
- the first plastids
- include chloroplastida and rhodophyte
What are chlorpolastids?
- include ‘green algae’ and land plants
- diverse
- small to large, most have carbohydrate scales or cells walls
–> prasinophytes: important in ocean, small flagellates, many have carbohydrate scales : scales made continuously by the cell, made intracellular
–> chlorphycae:
- mostly freshwater
- have thick cell walls to resist osmotic pressures
- a range of colonial forms
What are rhodophyta?
- red algae: have phycobilins
What are the classifications of archaeplastida?
- the first plastids
- chloroplastida: prasinophytes and chlorophycea (have chlroophyll b, not phycobilisomes)
- rhodophyte:
What are the chlorophyll c algae?
- stremenophile algae: diatoms
- haptophytes
- dinoflagellates : alveolate
Describe the chlorophyll c plastids
- all derived ultimately from secondary endosymbiosis of red algae
- 3 (or 4) membranes
- chlorophyll c (as well as a)
- have accessory pigments (lots of carotenoids) but no phycobilisomes
Describe haptophytes
usually small haptophytes: usually marine
- mixotrophs
- have haptonema: microtubule flagellates: sensing and food caputure
- usually carbohydrate scales or mineralized coccoliths
What are coccoliths?
- calcium carbonate scales
- major marine group: forms sediment when they die: contributes to geological cycling of carbon
How are coccoliths formed?
calcium carbonate deposited on an organic scale based within endomembrane system, then fuses with outer membrane and becomes a part of scales
What are stramenophiles?
- form of chlorophyll c algae
- unique flagellar hairs (mastigonemes) : hair on either side of flagella, reverses direction
What are mastigonemes?
- unique flagellar hairs on either side of flagella of a stramenophile, reverses direction of swim!
What are diatoms?
- a type of straminophile (Chi c algae)
- unicellular/colonial
- non flagellated (except some gametes)
- characteristic silica frustule
- pennates (benthic, dominate sediment) and centrics (planktonic)
- ecologically important in the sea
What is the diatom frustule?
- the box with lid structure of diatom : epitheca and hypotheca: valves and then girdle bands on the side
- life cycle: diploid dominant, each becomes the epitheta in the next: sexual process important for resizing the cell
What are the alveolates? What do they have?
- dinoflagellates : algae
- apicomplexa : parasite
- ciliophara : free living protozoa
- all have cortical alveoli: flattened vesicles under the membrane
What are dinoflagellates?
- type of algae
~1/2 have plastids (photosynthetic) - most are phagotrophic
- most toxic algae is dinoflagellates
- have theca plates: calcium carbonate in between the cortical alveoli
- have flagellates
What are apicomplexa?
- alveolate group: parasites
- major group of parasites (malaria, toxoplasmosis), usually invade host cell + complex life cycle (sexual, with more than one host species)
- life cycle: HAPLOID DOMINANT
- sporozoites (transmission phase) merozoites, gametes : in mosquitoes and humans
Provide an example of a haploid dominant and a diploid dominant life cycle
- apicomplexa malaria is haploid dominant
- silica frustule in diatoms are diploid dominant
What are ciliophora?
- alveolata: a free living protozoa, mostly have cilia and nuclear dualism
- nuclear dualism: micronuclei: one genotype, inactive, micronuclei: thousands of micronuclei
- sexual process: conjugation occurs where macronuclei (transcriptionally active, binary fission in asexcual reproduction) disintegrates, micronuclei undergo meiosis and are exchanged
What are some forms of ciliate diversity
- even covering on entire cell
or: sparse covering but large oral apparatus
Describe the types of amoeba groups
- foramonifera
- amoebozoa
- slime moulds
Describe foraminifera
- major amoeba group
- mostly marine : benthic or planktonic
- have elongated pseudopodia chains
- usually with multichambered test (shell) of calcium carbonate
pseudopodia: made from microtubules, shuttles organelles along
Describe amoebozoa
- major amoeba group
- actin based pseudopodia: usually thick or broad/flat
- important in sediment/soil
Describe cellular slime moulds
- many individual amoebas group together to form pseudoplasmodium
- most become spores, some sacrificed to become fruiting body
Describe heterotrophic flagellates
- default eukaryotes
- eg; choanoflagellates
What are choenoflagellates?
- default eukaryote : heterotrophic flagellates
- closest relative of animals
- best known opsthikont: animals and fungi
- collar surrounding flagellum
- important baceteriovore
Describe the collar of a choenoflagellate
- ring of actin supported microtubules around flagellum
- role: food particle collection
How much of ocean photosynthesis do cyanobacteria account for?
- ~50 % of total photosynthesis in the ocean
- there are more microorganisms in a ml than all of the ocean animals
Who eats prokaryotes in the ocean?
- mostly viruses, and protists: heterotrophic flagella, and mixotrophic flagellates
Describe fungi
- opisthokonts: related to animals and choanoflagellates
- diverse: most are not phagotrophic: absorb nutrients
- many multicellular or coenocytic, some with large fruiting bodies
= most terrestrial : important in decomposition or parasitic - non flagellated / non motile
- many filamentous: mass of hyphae = mycelium
- sexual (fruiting body) and asexual (spores)
- cell body with chitin: resist osmotic pressure and turgor allows growth/pentration
how do fungi typically grow?
- penetrative hyphen growth via turgour
Describe the hyphae of fungi
- branching filaments
apical zone: the tip, growth - absorption zone a little behind
- can grow so fast: speed of a small microbe
- coenocytic or septet EXCEPT yeasts
Describe yeasts
- unicellular fungi: most bud when reproducing asexually
What is the nutrition and absorption of fungi like?
- saprotrophs: secrete digestive eco nzymes that break it down and then absorb it
OR
absorb it directly
What are saprotrophs?
- like fungi, secrete digestive e(exo) enzymes to break down and absorb nutrients
Describe the fungi life cycle
- lifecycle haploid dominant
- sexual process requires fusion of haploid (karyogamy) followed by production of sexual spores
- asexual reproduction widespread: small, dispersive, resistant to dessication
What are the types of fungi?
- chytrids
- zygomycetes
- glomeromycota
higher fungi
- basidiomycota
- asomycota
Describe zygomycetes
- a type of fungi
- mostly filamentous and hyphae coenocytic, grow on sugar rich substrates (bread, food stuffs)
What is some extra information on basidiomycetes?
- eukaryotic mycelium and long lived before fruiting body (fairy ring)
Describe basidiomycetes and ascomycetes?
- septate hyphae
- dikaryotes: dikaryon becomes fruiting body which forms fused nucleus zygote that undergoes meiosis to become hames
What is mycorrhizae? What is arbuscular mycorrhizae?
- mycorrhizae is symbiotic fungi plant relationship : in >80% of vascular plants so not rare
- arbsucular: most common form of endomychorrizae : hyphae penetrates cell wall not cell membrane: benefit to plant = nutrients, SA for water absorption , benefit to fungi = stable source of organic carbon
What are macro algae?
- large plant like algae
- thallus (main body) macroscopic, multicellular, attached via holdfast
- evolved many times: green, red, brown
Describe land plants and aquatic plants
- sheer forces relatively low, faced with gravity, nutrients and water from soil, transpiration in roots
- gravity trivial (buoyancy), hold fast for attachment, nutrients and water from surroundings, strong sheer forces
Describe the cell wall / extracellular matrix of macro algae?
- cell wall typically a large part of the thallus, important for structural support: largely made of polyaccharides
What are some basic forms of the thallus?
- filamentous (one to a few cells thick)
- sheet-like (one to two cells)
- fleshy: differentiated: often outer cell wall part of photosynthesis
Describe filamentous algae
- simple / branching filaments
- thickened/feathery
- typically division of apical meristem cells: one plane of division: mitosis, division
- lateral division determinate
Describe fleshy algae
- pseudoparenchymatous: grows in filaments within one extracellular matrix = like a mitten
- parenchymatous: 2+ planes of division from meristem = true tissue
Describe the types of intracellular connections between macro algae
- plasmodesmata in many green macro algae (chloroplastidan) and some brown:
- pit plug in red macro algae: more mechanical? - looks like cell stopped right before diving completely
Describe the macroalgal life cycle
- sporophyte (2N) –> spores –> Gametophyte -(gametes)-> zygotę –
- sometimes (not always) alternation of generation
- sporophyte and gametophyte may be isomorphic or heteromorphic (different)
Describe the chlorplastida macro algae
- ‘green algae’
–> Ulvaphcae - main form of green algae found in marine
eg; ulva : thallus 1-2 cells thick
eg; caulerpales: some with complex thick thalli, siphonous: continuous multinucleate cytoplasm branching through thallus
Describe rhodophyte macro algae
red algae
- completely lack flagella (male gametes non motile)
- plasmiod plastids
- most pseudo parenchymatous or filamentous
- thick extracellular matrix common
What are the types of rhodophytes
- Porphyra
- florideophycea
Describe porphyra
- highly heteromorphic
- gamete: large sheet like thallus (nori: sushi)
- sporophyte: small, filamentous
Describe the florideophycean (triphasic) life cycle
- haploid gametophytes plus two sequential diploid phases:
1) carposphorocyle : small, attached to gametophyte, produces carpospores (diploid)
2) tetrasporophyle: normal macroalgal sporophyte - produces haploid tetradpotes
Describe one florideophycean example
eg; corralinales
- pseudo parenchymatous
- has CaCO2 deposits in extractllular matrix
- resistant to grazing, cement coral together, slow growing and resilient, important reef constructor
Describe brown algae
- a subgroup of stramenophiles
- mostly marine: simple to largest/most complex macro algae
Describe phyeophycae as stramenophiles
- secondary plasstids like those of other stramenophiles (eg; 4 membranes, stacked thylakoids, chlorophyll a and c, etc)
- spores and motile gametes have stremaenophile type hairs on one flagellum (mastigonemes: move backwards)
Describe laminaries
-Kelps
- sporophytes often large : distinct sipes and blades (2N)
- tiny gametophyte (ie:hetermorphy!)
- they have a parenchymatous thallus: blade and stipe grown in length from intercalary meristem + distinct tissue layers
- they also have trumpet hyphae
What are trumpet hyphae?
- connected end to end to form a sieve tube
- AKA sieve elements: helps move materials rapidly = large growth
- within. medulla
- transports energy rich organic molecules (like plant phloem)
What is one example of laminaries?
macrosystis: giant kelp
- stripe connects to blade: pneumatocyst (small gas filled bladder) is at junction point between blade and stipe
- allows for buoyancy and photosynthesis
What is unique about rhodophyte specifically when it comes to gametes?
- completely AFLAGELLATED: gametes are non-motile!!
Describe pseudomonads
- a type of proteobacteria
- facultative anaerobe
- limited fermentation abilities
–> anaerobic respiration with various electron acceptors
eg; pseudomonas aeruginosa: found in soil, facultative pathogen in CF and burn wounds!
What are archaea?
- prokaryotes like bacteria but with many archaea features
- also share some features with eukaryotes
- many are extremophiles!
What makes up standard eukaryotic and bacterial cell envelopes?
- glycerol-3-phosphate backbone
- fatty acids
- ester linkages
How do archaea membrane lipids differ?
- ether linkages
- isoprenoid units (not fatty acids)
- stereochemically opposite backbone (on glycerol 1 phosphate)
- very different structure!
Describe the archaeal cell envelope?
- no true peptidoglycan and no outer membrane
- pseudopeptidoglycan: chemically different cell wall in a few Arachne
- s layers common
Why are archaea fundamentally prokaryotes?
- single circular genome with operons, small cell, coupled transcription and translation, AND WAIT UNTIL I TELL YOU…. few internal cell structures!!!!!!
- but there are some major differences: typical archaean like characteristics and eukaryotic characteristics
What are some eukaryotic like features of archaea?
- similar transcription and translation machinery:
transcription: many eukaryotic like subunit RNA polymerase and eukaryotic like transcription factors (TATA Binding Protein)
translation machinery:
- many eukaryotic / archaea specific ribosomal proteins
- METHIONENE as inditiatior amino acid (bacteria use FMET)
What do the similarities between archaea and eukaryotes indicate?
- they have a close phylogenetic relationship
- hypothesizes that eukaryotes arose within Archaea!
What are the two best known groups of archaea?
- crenarchaeota and euryarchaota
What are some of the kinds of archaea?
thermophiles: most crenarchaeota, some euryarchaeota
halophiles (haloarchaea)
methanogens (methane makers): mostly euryarchaeota, some others
Describe thermophiles
- mainly crenarchaeota
- some live >90 C (hyperthermophiles)
- many thermophiles are lithotrophs
- habitats: geothermal vents, hot springs, etc
- H2 + So –> h2S
how do thermophiles survive extreme temperatures?
-membranes: increased rigidity and integrity (prevents fluidity from increased warmth)
- archaean membranes: isoprene units and ether bonds make it more stable, isoprene tails linked in some archaea
What are tetra ethers?
example of bonds between isoprene unit tails
- thermostable enzymes and other proteins: structurally stable and active at high temperatures
- Reverse gyros also induces positive DNA supercoiling to prevent DNA denaturation
What group is the closest relative to eukaryotes?
- asgard
Describe methanogens
- CH4 is a product of energy metabolism
- most methanogens are euryarchaotes
- obligate anaerobes (most are STRICT anaerobes)
(low energy yield)
Methanogenesis as an energy pathway:
4 H2 + CO2 –> 2H2O + CH4 (CO2 is electron acceptor)
- low energy yield
What are some habitats of methanogens?
- wetlands, marine sediments, marshes, rice paddies, guts of animals (ruminants and termites)
- contribute to most biological methane emissions
- increased methane emissions comes from human increased archaic habitats (cow production)
